Grain boundary analysis of MgO-doped Al2O3

Franken, P.E.C.; Gehring, Albrecht

doi:10.1007/bf00738627

Cited by 22 publications

(5 citation statements)

References 8 publications

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“…Indeed, the only studies in which Mg enrichment has been detected are those in which a Mg-rich boundary phase is suspected [17][18][19][20][21][22] or extremely slow cooling rates have been used ͑200°C/h͒. 13,14 This letter presents conclusive evidence for Mg segregation in a rapidly cooled polycrystalline Al 2 O 3 doped to a level below the solubility limit.…”

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confidence: 90%

Solute segregation to grain boundaries in MgO-doped alumina

Soni

Thompson

Harmer

et al. 1995

Applied Physics Letters

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The spatial distribution of Mg solute in polycrystalline, single-phase Al2O3 has been obtained, using a secondary ion imaging technique. Segregation of Mg to the Al2O3 grain boundaries is clearly observed—strong evidence that the principal role of MgO is to reduce the grain boundary mobility via a solute-drag mechanism. In addition, Mg (dopant) and Ca (impurity) are shown to cosegregate, shedding further light on magnesium’s ability to stabilize microstructural evolution in Al2O3.

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confidence: 90%

Solute segregation to grain boundaries in MgO-doped alumina

Soni

Thompson

Harmer

et al. 1995

Applied Physics Letters

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“…Doping of several metal/metal oxides even at ppm level into the Al 2 O 3 matrix can alter the sintering behaviour by influencing the rate of densification and the associated change in the activation energies of sintering [17–19]. The role of dopants on the microstructure refinement of Al 2 O 3 is well known; the impact of doping Y 2 O 3 , ZrO 2 , and MgO on the densification and grain growth of Al 2 O 3 has been demonstrated previously [17, 20–22]. Also, the nature and mobility of dopant atoms within the interface play a vital role in determining the properties of the doped system.…”

Section: Introductionmentioning

confidence: 99%

Sintering, microstructure, and mechanical properties of ZrO₂-doped Al₂O₃

Baruah,

Anand,

Behera

2023

Advances in Applied Ceramics: Structural, Functional and Biocer

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In the present work, the effect of Zr-doping on the sintering, microstructure development, and mechanical properties of polycrystalline Al 2 O 3 was studied. Dopant concentrations of 830 and 2070ppm cationic ratio of Zr in Al 2 O 3 corresponding to 2000 and 5000 wt. ppm of ZrO 2 in Al 2 O 3 , respectively, were used. The sintering schedule of undoped as well as Zr-doped Al 2 O 3 samples was optimised following a series of precoarsening experiments. The Zr-doped Al 2 O 3 ceramics exhibited controlled grain size and improved density. Upon increasing the Zrdopant concentration from 830 cat. ppm to 2070 cat. ppm. Zr-doped Al 2 O 3 ceramics having a refined microstructure with a homogeneous distribution of controllably grown ZrO 2 in Al 2 O 3 matrix was obtained. Microhardness of the Zr-doped samples showed negligible dependence with Zr-doping, whereas mechanical strength was found to improve with it. The improvement in strength was attributed to the combined effect of improved sinter density, microstructural refinement, and grain-boundary strengthening.

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“…Because of the low concentrations needed, proper distribution of the MgO is difficult to attain and is critical to the properties of the resulting material. A number of methods have been used using Mg‐containing chemicals, such as Mg‐nitrates, 3–6 Mg‐stearates, 6 Mg‐acetates, 6–8 and Mg‐carbonates 9,10 . In most studies, these chemicals were dissolved in a solvent or water prior to being mixed with alumina powders.…”

Section: Introductionmentioning

confidence: 99%

Injection‐Molded Alumina Prepared with Mg‐Containing Binders

Hwang

Hsieh

2005

Journal of the American Ceramic Society

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It is generally accepted that MgO additions enhance the sintering of alumina. The distribution of the low concentration required is, however, difficult to attain and critical to the final properties and microstructures. To improve the MgO distributions in ceramic injection-molded (CIM) alumina, Mg-containing precursors, Mg-stearate and Mg-acetate, were added during the kneading step of the CIM process, and the results were compared with those from adding MgO particles. Of the three additives, the Mg-stearate showed the highest sintered density and bending strength. This was attributed to its high molecular weight and it being able to mix with other binder components homogeneously in the liquid state, which leads to a better distribution of the MgO. In contrast, the MgO powder was kneaded in the solid particle form, and its distribution was not uniform. The Mg-acetate also imparted poorer MgO distribution because the liquid Mg-acetate dehydrated in the early stage of the kneading and formed solid lumps before it was well mixed into the binder system. The resulting sintered densities and bending strength using these two additives were, therefore, inferior to those for specimens in which Mg-stearate was used. 2349J ournal

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Grain boundary analysis of MgO-doped Al2O3

Cited by 22 publications

References 8 publications

Solute segregation to grain boundaries in MgO-doped alumina

Solute segregation to grain boundaries in MgO-doped alumina

Sintering, microstructure, and mechanical properties of ZrO₂-doped Al₂O₃

Injection‐Molded Alumina Prepared with Mg‐Containing Binders

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Grain boundary analysis of MgO-doped Al2O3

Cited by 22 publications

References 8 publications

Solute segregation to grain boundaries in MgO-doped alumina

Solute segregation to grain boundaries in MgO-doped alumina

Sintering, microstructure, and mechanical properties of ZrO2-doped Al2O3

Injection‐Molded Alumina Prepared with Mg‐Containing Binders

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Sintering, microstructure, and mechanical properties of ZrO₂-doped Al₂O₃